1. Field of the Invention
This invention relates generally to measuring the torsional and bending capabilities of the lower extremities of a human body and, particularly, to measuring said capabilities to the limit of significant pain or discomfort experienced by a subject in response to self-applied torsional and bending forces. More particularly, this invention relates to measurements of the type described which may be correlated or calibrated for a variety of purposes desired. Still more particularly this invention relates to measurements of the type described which may be calibrated for adjusting releaseable ski boot bindings whereby excessive torsional or bending forces experienced during, for example, a fall of a skier will release the skiers boot from the ski to reduce the risk of serious injury which might otherwise occur.
2. Description of the Prior Art
The sport of alpine skiing is such that releaseable ski boot bindings are in general acceptance to reduce the risk of injury to the skier which might occur during a fall or the like. A device for accomplishing this purpose is described in U.S. Pat. No. 3,764,155 issued on Oct. 9, 1973 to John S. Perryman, the inventor of the present invention, and which patent describes and claims a releaseable ski boot binding which will release the boot from the ski in response to excessive torsional and bending forces exerted upon the lower extremities of the skier. Likewise, U.S. Pat. No. 3,764,154 issued on Oct. 9, 1973 to Gerhard Whitting describes and claims a releaseable ski boot binding which reduces the boot from the ski when the retaining forces of the binding exceed given maximum values.
While the releasability of the ski bindings described in the aforenoted patents is adjustable, depending upon a variety of conditions, there has not heretofore been a means or method for adapting the adjustment to the capabilities of the individual skier. In most cases the adjustment is made utilizing general physical parameters such as weight, tibia bone diameter, sex, age, ability, skiing speed and such other factors as are discernable to those skilled in the art. The difficulty arises in the fact that the utilization of these parameters for the purposes intended is based on judgement (qualitative) rather than on measurement (quantitative). Accordingly, the results provided are relatively inaccurate and no not provide the maximum margin of safety while providing adequate ski binding retention for normal skiing. Typical of the prior art devices is that described and claimed in U.S. Pat. No. 3,389,472 issued on Dec. 6, 1966 to C. C. Lipe, et. al., wherein means are provided for adjusting the releaseability of the ski binding within a degree of safety consistent with the limits of the skiers ability, weight, age, physical condition and experience.
The prior art devices, however, do not take into account certain generally accepted facts that most healthy people will experience discomfort, pain, strain, sprain and then bone fracture, generally in that order, if undue loads are applied to their lower extremities as during a serious fall when skiing. It is also a generally accepted fact that a skier need not exert any more force for controlling his skis then he is physically able to apply within his own threshold of discomfort or pain.
The present invention recognizes that torsional and bending forces are the significant traumatic forces applied to the lower extremities of a skier for causing most injury producing accidents. Accordingly, the invention provides a means and method for measuring the torsional and bending capabilities of the lower extremities to the limit of significant discomfort and pain within the skiers individual threshold. The torsional and bending forces are applied through the skiers own muscular strength and measurements are achieved for his own individual capabilities, and which measurements may be used for adjusting ski binding releaseability or, in other words, used as ski binding retention indices.